FANUC A06B-6240-H105 AC Servo Amplifier Unit — αiSV 80-B, Single-Axis, 200V Series

Part No.: A06B-6240-H105  |  Model: αiSV 80-B  |  Series: FANUC αi-B  |  Type: Single-Axis Servo Amplifier Module  |  Origin: Japan

Overview

Axis control that falls short isn't axis control — it's a liability. The FANUC A06B-6240-H105 is a single-axis AC servo amplifier module from FANUC's αi-B series, model designation αiSV 80-B, built for high-demand CNC and robot applications where consistent torque, clean high-speed response, and long service intervals are non-negotiable.

The αi-B series sits at the core of FANUC's modern servo architecture. Compared to earlier generations, the series runs cooler, takes up less cabinet space, and draws less power for equivalent output — FANUC reduced amplifier installation footprint by approximately 30% versus conventional designs through a combination of low-loss power devices and a redesigned heat-dissipation fin. In practice, that means more drive capacity per rack and better thermal management in dense multi-axis cabinet configurations.

The A06B-6240-H105 is used across two main deployment contexts: as a CNC servo axis drive in machining centres running FANUC Series 30i, 31i, and 32i controls, and as an auxiliary or 7th-axis amplifier in FANUC robot systems — specifically R-30iB and R-30iB Plus controller configurations where additional servo axes are required beyond the standard six. In both roles, it operates as part of a coordinated FSSB (FANUC Serial Servo Bus) fibre-optic communication chain, receiving axis commands at high speed with minimal latency.

Technical Specifications

Built for the αi-B Architecture — What That Means in Practice

The A06B-6240-H105 is not a standalone drive in the traditional sense. It is a module within a coordinated FANUC servo system, and understanding how it fits into that system determines everything from installation procedure to replacement strategy.

FSSB Fibre-Optic Communication The amplifier communicates with the CNC or robot controller over FANUC's high-speed serial servo bus, carried on fibre-optic cable rather than conventional copper wiring. Fibre eliminates electromagnetic interference between the signal and the high-power switching noise inherent in the power stage — important in compact cabinets where signal and power cabling share confined space. The communication cycle runs fast enough to support precise multi-axis synchronisation without the dead-band limitations of older pulse-train architectures.

Shared DC Bus Architecture The αi-B series uses a shared DC bus configuration: the αiPS-B power supply module rectifies incoming AC and feeds a common DC rail to which multiple servo and spindle amplifier modules connect. The A06B-6240-H105 draws from this shared bus rather than rectifying its own input from mains AC. This has two significant consequences. First, regenerative energy from one decelerating axis can be absorbed by an accelerating axis on the same bus, reducing net power drawn from the supply. Second, replacing the amplifier module does not require replacing the power supply — assuming the PSM is healthy and correctly rated for the total axis current demand.

Built-In Absolute Pulsecoder Capacitor A backup capacitor inside the A06B-6240-H105 holds the absolute encoder position for approximately 10 minutes after power removal. This means that in normal operation — replacing the amplifier module itself — reference position return is not required after reinstallation, provided the swap is completed within the capacitor's hold time. On machines where homing cycles are time-consuming or require fixture clearance operations, this feature alone saves meaningful time during planned maintenance.

Fan Cooling with Monitoring Active fan cooling maintains the power stage within operating limits under sustained high-current demand. The drive monitors fan status and can flag fan fault conditions before thermal shutdown occurs — giving maintenance teams time to schedule intervention rather than experiencing an unplanned trip.

Where This Amplifier Gets Installed

CNC Machining Centres — High-Power Feed Axes The 80-designation in αiSV 80-B refers to the drive's power class. At 22.5 A rated output, the A06B-6240-H105 is suited to X, Y, Z, and rotary axis drives on mid-to-large machining centres where axis thrust or torque requirements exceed what smaller amplifier variants in the 40 or 20 class can deliver. Linear axes on horizontal machining centres, rotary pallet tables, and heavy-feed applications on 5-axis machines all draw on drive capacity in this range.

FANUC Robot Systems — Auxiliary Axis Expansion One of the most common installation scenarios for the A06B-6240-H105 is as a 7th or additional axis amplifier in robot workcells controlled by an R-30iB or R-30iB Plus controller. Track systems, rotary positioners, servo weld guns, and servo-driven tool changers all require an additional amplifier module outside the robot's internal drive for the base six axes. The A06B-6240-H105 connects to the FSSB chain in the controller cabinet and is configured as an additional axis in the robot parameters.

Multi-Axis Flexible Manufacturing In gantry systems, transfer machines, and flexible manufacturing cells where FANUC Power Motion i-A or Series 31i controls coordinate multiple linear and rotary axes simultaneously, the A06B-6240-H105 fills the high-current axis slots in mixed-capacity drive configurations — running alongside smaller αiSV 40-B or αiSV 20-B modules that handle lower-torque axes on the same shared bus.

Fault Diagnosis — What the LED Status Display Tells You

Every αi-B series amplifier has a front-panel LED display that provides real-time status and alarm information. After a fault trip, the displayed alarm code is the first and most direct diagnostic pointer. Common codes relevant to the A06B-6240-H105 and their most frequent root causes:

Alarm 9 (Overvoltage on DC bus): DC bus voltage has exceeded the allowable limit. Most commonly caused by insufficient regenerative capacity — either the power supply module's regenerative circuit is saturated, or deceleration ramps are too aggressive for the inertia being stopped. Check the αiPS module status and consider a regenerative discharge unit if the application involves frequent hard decelerations.

Alarm 6 (Overcurrent): Output current exceeded the threshold. Check motor wiring — particularly the U, V, W connections — for insulation breakdown, intermittent short, or incorrect phasing. Also check the motor itself if the alarm appears at a consistent point in the axis movement cycle.

Alarm 1 (Fan fault): Internal cooling fan has stopped or slowed below the minimum speed threshold. Replace the fan before continuing operation; running at high current without adequate cooling risks thermal damage to the IGBT power stage.

Alarm 8 (High temperature): Power stage temperature has exceeded the safe limit. Check ambient temperature in the cabinet, ensure the fin is clean and not obstructed, verify that the fan is running, and confirm that the drive is not exceeding its rated output current for the duty cycle being run.

Part Number Search Variants

Buyers searching for this module use several formats — all refer to the same unit:

A06B-6240-H105 · A06B6240H105 · A06B-6240-H105 · AO6B-624O-HIO5 (O/zero confusion — common OCR misread, same product) · FANUC αiSV 80-B · aiSV80B amplifier · FANUC 6240 H105

Shipping & Dispatch

Units ship in original FANUC factory packaging within 1–2 business days of confirmed payment. Express carriers are available for urgent requirements.

Carriers: DHL Express · FedEx International Priority · UPS · EMS · TNT Transit: 3–7 business days to most international destinations via express Documentation: Commercial invoice and packing list standard; certificate of origin on request Import duties and taxes: Payable by the buyer at destination

Tracking numbers are provided as soon as the shipment is collected.

Frequently Asked Questions

Q: What is the difference between the A06B-6240-H105 and the A06B-6290-H105?

A: Both are single-axis αiSV 80 servo amplifier modules in the αi-B series, but they operate in entirely different voltage classes. The A06B-6240-H105 is the 200 V input series variant — it connects to an αiPS-B power supply that feeds a 283–339 V DC bus, and it outputs 240 V AC to the motor. The A06B-6290-H105 is the 400 V HV (high-voltage) input series variant — it operates from a 537–679 V DC bus and outputs 400 V AC. They are not electrically interchangeable. Your installation's power supply module and the voltage rating of the servo motors in the system determine which variant is correct. Using a 200 V series amplifier on a 400 V bus will destroy the module.

Q: Can the A06B-6240-H105 be used as a replacement in a FANUC R-30iA robot controller?

A: The A06B-6240-H105 is designed for the αi-B series architecture, which is associated with the R-30iB and R-30iB Plus controllers. The earlier R-30iA controller used αi series (non-B) amplifiers in its servo cabinet. While the physical form factor is similar, the αi-B series has revised communication timing and bus characteristics versus the original αi series. Mixing B-series and non-B-series modules in the same system is not a supported configuration. Verify the controller generation and the existing amplifier series before ordering a replacement — match the suffix of the installed modules exactly.

Q: The machine shows a servo alarm after I replaced the A06B-6240-H105. What should I check first?

A: The most common cause of a servo alarm immediately after a module swap is the motor reference position data. Even though the αi-B series has a built-in backup capacitor to hold absolute encoder position, if the replacement takes longer than approximately 10 minutes with power removed, the capacitor will discharge and the absolute position data is lost — requiring a reference position return cycle before the axis can run. Check the CNC or controller alarm message for position error or absolute data loss codes first. If an alarm unrelated to position data is shown, check that all FSSB fibre-optic connectors are fully seated (both on the amplifier and on the adjacent modules in the chain), and verify that the CNC axis parameter configuration matches the new module.

Q: Does this amplifier include a built-in regenerative resistor?

A: No. In the αi-B series architecture, regenerative energy handling is managed by the shared power supply module (αiPS-B) rather than by individual axis amplifier modules. The PSM handles regeneration for the entire bus. If the regenerative capacity of the PSM is insufficient for the application — typically indicated by DC bus overvoltage alarms during hard decelerations — a regenerative discharge unit can be added to the system. Individual axis amplifier modules in the αi-B 200 V series do not have their own regenerative resistors or brake choppers.

Q: How do I confirm this is the correct part before ordering — what markings should I look for on the existing module?

A: The FANUC part number is printed on the label affixed to the front or side face of the amplifier module, in the standard A06B-XXXX-HXXX format. If the label reads A06B-6240-H105, this listing is the direct replacement. Additionally, confirm the model designation on the label — it should show αiSV 80-B. If you are sourcing the part based on a spare parts list rather than an installed module, cross-check the CNC axis configuration parameter (the amplifier model code stored in the CNC's servo parameter settings) to verify the drive model the controller is expecting. If there is any uncertainty, share the machine model, CNC generation, and cabinet wiring diagram reference with our team before placing the order.